I am just finishing up a Trex 700E with the Custom Heli Parts Direct to Swash frames and Outrage Torq Servos all round. The cyclics are fine and see to be very fast, running off a 2S LiPo connected directly through the power bus. However, the BL9188 Tail servo is extremely rough and makes a lot of noise, as well as transmitting a lot of vibration down the carbon tail control rod. It is set up in the Skookum wizards as a custom servo, 333Hz, 760micro secs pulse width.

There was a post I found somewhere saying that this had been seen with V-Bar and that you should just fly with it like this - I can no longer locate that post, but I just don't feel comfortable with it the way it is. Any Ideas? Should I just send it back to HeliDirect where I got it? Even without the linkage connected it still feels rough/ratchety. I also found posts suggesting to increase the deadband slightly to quiet down the twitchiness when there is no input from the radio, but this had no effect.

There is a video of Lukas Riva on you tube running these servos with a Velocity 90 and an SK720 so it doesn't look like there is any compatibility issues between the Skookum (except for the max frequency being only 333Hz instead of 560hz

I just installed mine (outrage 9188) yesterday that I received mine from helidirest. I flew my 550 yesterday and the day was spot on solid and handled everything I could throw at it. I checked it upon landing and it was still ratchity and noisy so I'm saying screw it, its fine and obviously just a noisy beast in nature.

I tried changing the receiver frequency between 1024 and 2048 but that made no difference. It is supposed to also be an issue with V-Bar. I am wondering if it has something to do with how the SK720 communicates with the servo during setup vs when it is flying due to the narrow pulse width of this servo. This is the first 760 servo I have used.

I just don't feel comfortable flying with the tail making this much grinding noise. The same tail and boom was on my regular 700E and had no issues (smooth as silk) and so it is not the tail slider or anything back there.

I am going to try running this servo off my BeastX to see if that makes any difference and I will report back.

Here is the thread where I originally saw this being a known issue, but have not been able to tract it down further in the V-bar thread yet.

Yep That is exactly the config I have, carbon (look alike anyhow) boom and Carbon tail control rod and it sounds absolutely horrible, I am going to try it tentatively in a simple hover as soon as I get the governor set up (Scorpion Commander V130A with phase sensor feeding the SK720).

I will report back - just hard to get used to the idea of flying a helicopter with this kind of grinding mechanical noise. All the reports though says that it flys awesome and very smooth.

Thats what all the reports say so I will bite the bullet and put it in the air in the next few days and let you all know how it goes. I am thinking of building a Goblin with these servos on it so this will be a much cheaper test bed to figure it all out. Hope to do the Beast X test tonight or tomorrow too.

I just finished the test of the Outrage Torq BL9188 with my BeastX (actually an AR7200BX) which is on my stretched 450Pro. I just unplugged that tail servo, reprogrammed the AR7200BX to 760 micro secs pulse width and 560Hz frequency, and plugged in the BL9188.

The result is much smoother (not completely quiet) but definitely acceptable. So now the question - is it the frequency issue on the SK that is making this worse? Anyone know what frequency options the V-Bar offers as this grinding noise is supposed to be an issue on the V-Bar too.

Art - What are the chances of getting a 560Hz option into the SK720 anytime soon?

Now on to complete the 700E Direct to Swash project and see how the tail actually flies.